This invention relates generally to sliding clasp fasteners and in particular to a sliding clasp fastener of the type having a pair of rows of interlocking elements formed from a plastics filament into a meander structure.
In a sliding clasp fastener including a row of meander-type elements produced by bending a plastics filament, it is the customary practice to attach the elements by bonding or fusing to a stringer tape. However, this process of attachment has the drawback that due to extremely limited areas of contact between the tape and the elements, the elements are liable to disengage from the tape when subjected to severe external stresses. Various attempts have heretofore been made to explore more effective and secure attachment of the fastener elements other than by adhesive bonding or fusing. Normally, such attempts have involved additional manufacturing steps as regards a particular area of the tape at which the row of interlocking elements is to be mounted. One such attempt was to form a corrugated surface on a marginal edge portion of the tape in order to ensure increased mating engagement of the row of interlocking elements with the tape. Another attempt included, in addition to the bonding or fusing treatment, the provision of a plurality of apertures in the tape for passing the sewing threads that secure the elements to the tape. However, these prior-art efforts have only led to complicated, time-consuming manufacturing operation. Furthermore, with the construction of the prior-art sliding clasp fastener, the fabric of the tape adjacent the row of elements has suffered from wear or damage in repeated frictional engagement with a reciprocating slider.